1. Field of the Invention
The present invention relates to an apparatus used to lubricate the rails of a railway track, and more specifically to such an apparatus which is located on or in the ground next to the rails to be lubricated and which is activated by the passing of the wheels of a railway vehicle thereby. In particular, the present invention is directed to such a lubricating apparatus which operates as the result of the forced internal circulation of a hydraulic fluid.
2. Description of the Prior Art
Lubricating devices which are positioned next to the rails of a railway track and which are activated by the passage of the wheels of a railway vehicle thereover to discharge a lubricant onto the rail head are well known, the application of lubricant to the rails having long ago been found to reduce the frictional wear on the rail head and the degree of noise resulting from contact between the vehicle wheels (especially the wheel flanges) and the rail head. Many of the known lubricating devices include a lubricant-containing supply tank located in the ground near the rail, one or more lubricant distributing elements positioned on one side of the rail, a pump in the supply tank capable of conveying lubricant through one or more pipes to the lubricant distributing elements, and an actuator element located along the length of the rail and suitably connected to the pump to operate it in response to the passage thereover of a railway vehicle wheel.
In some of these prior art lubricating devices the connection between the actuator element and the pump in the supply tank is purely mechanical, utilizing an elongated rotatable drive rod with attendant joints, springs, bearings, etc. However, these mechanical components deteriorate in time due to wear and tear, and since in order to function they must necessarily be located above the ground next to the rail, they are easily damaged by vehicle derailment or dragging equipment. Thus, lubricating systems using these mechanical connections are often not desirable.
Other lubricating devices are known wherein the connection between the actuator element and the pump in the supply tank consists of either a single hydraulic fluid line or a recirculating fluid loop in which a hydraulic fluid such as a light oil is caused to flow by the activation of the actuator element. A device of the former type is shown in U.S. Pat. No. 2,355,241 to Rodman et al wherein a single pipe connects the actuator element to the pump in the lubricant supply tank and wherein activation of the actuator element causes a hydraulic fluid to flow from the actuator element through the pipe towards the pump so as to operate it. However, in this system both the actuator element and the pump function by the expansion and contraction of bellows elements therein, and these bellows elements will break down over time due to the experienced expansion and contraction stresses, necessitating inconvenient and costly replacement.
A device of the latter type is shown in U.S. Pat. No. 2,401,303 to Huber wherein a recirculating fluid loop connects the actuator element to the pump in the lubricant supply tank and wherein activation of the actuator element causes a hydraulic fluid to flow through the loop to operate the pump. However, the actuator element used is very complicated in construction and thus expensive and difficult to service, and the pump, being in the form of a gun pump, has an intricate internal mechanism and is subject to troublesome breakdown.
It is thus an object of the present invention to provide a lubricating apparatus for the rail of a railway track which will be reliable, simple in construction, relatively inexpensive, and protectable from damage due to vehicle derailment and/or physical impacts resulting from dragging equipment.